An ulcer is a break in a skin or a mucus membrane evident by a loss of surface tissue, tissue disintegration, necrosis of epithelial tissue, nerve damage and pus. On patients with long-standing diabetes and with poor glycemic control, a common condition is diabetic foot ulcer, symptoms of which include surface lesions with peripheral neuropathy, arterial insufficiency, and ischemia of surrounding tissue, deformities, cellulitis tissue formation and inflammation. Cellulitis tissue includes callous and fibrotic tissue. If left untreated a diabetic foot ulcer can become infected and gangrenous which can result in disfiguring scars, foot deformity, and/or amputation.
As illustrated in FIG. 1A, a diabetic foot ulcer may develop on areas of the foot subjected to pressure or injury such as on the dorsal portion of the toes, the pad of the foot, and the heel. Depending on its severity, the condition can vary in size, as illustrated in FIG. 1B, from a small inflammation on the toe with cellulitis and unhealthy tissue that extends up to about 10 mm from the center of the inflammation, to a larger neuropathic lesion on the ball of the foot characterized by cellulitis and unhealthy tissue that extends beyond 2 cm of the perimeter of the perimeter. If the ulcer is accompanied by asteomeylitis, deep abscess or critical ischema, the condition may trigger amputation.
To assist in procedures for treating diabetic foot ulcers, one of several available grading systems such as the Wagner Ulcer Classification System shown in Table 1, below, is used to assess the severity of the ulcer and prescribe treatment. In making the assessment, the ulcer is examined to establish its location, size, depth, and appearance to determine whether it is neuropathic, ischemic, or neuro-ischemic. Depending on the diagnosis, an antibiotic is administered and if further treatment is necessary, the symptomatic area is treated more aggressively, for example, by debridement of unhealthy tissue to induce blood flow and to expose healthy underlying tendons and bone. If warranted, post-debridement treatment such as dressings, foams, hydrocolloids, genetically engineered platelet-derived growth factor becaplermin and bio-engineered skins and the like are applied.
TABLE 1Wagner Ulcer Classification SystemGradeClassificationType of Lesion0No open lesion (may have some cellulitis)1Superficial (partial or full thickness cellulitis)2Ulcer extension to ligament, tendon, joint capsulewithout abscess or osteomyelitis3Deep ulcer with abscess, osteomyelitis, or joint sepsis4Gangrene localized to portion of forefoot or heel5Extensive gangrenous involvement of the entire foot
In treating ulcers including diabetic foot ulcers, it has been recognized that early intervention to treat affected tissue before a lesion breaks out is beneficial, particularly to debride tissue, increase blood flow and stimulate healthy tissue growth. Topical debriding enzymes are sometime used but are expensive and have not been conclusively shown to be beneficial. After the condition has progressed to a lesion with extensive cellulitis, later stage intervention is also beneficial if the treatment involves removal of unhealthy tissue, increasing blood flow, and stimulating healthy tissue growth. It is therefore an objective to provide methods and systems to facilitate these goals.